The field of the invention relates to a transformer and/or inductor core. The transformer and/or inductor core may be inexpensively manufactured and provides for low power losses. In addition, the core may be easily designed using magnetic materials that provide improved efficiencies at high frequencies
Typical prior art transformer and inductor cores include laminations of ferro-magnetic material assembled into loops that form magnetic circuits. These magnetic circuits may be completely closed or may include air-gaps. Many prior art transformer and inductor cores may be considered discrete rectangular pieces of laminated magnetic material that together form the overall shape of the core. For example, magnetic cores may take the form of an “E” shape formed from five discrete rectangular core components (with a piece to close the open gap) or a “U” shape formed from four discrete rectangular core components (with a piece to close the open gap). An alternative method to forming the magnetic core is to wind magnetic metal ribbon into a toroidal ring or oval. Coil windings are positioned upon the cores to complete the inductors or transformers. Examples of prior art transformer and inductor cores are shown in FIGS. 1A–D.
In building transformer or inductor cores, all legs of the core (including any connecting portion that joins two coil wound legs) are typically of the same cross-sectional area. This allows the lines of magnetic flux to pass equally through the core with as little loss as possible. Unfortunately, this also means that the connecting portions of the core are large and add bulk to the core. It would therefore be advantageous to provide a transformer and/or inductor core arranged such that the overall size of the inductor or transformer could be reduced.
The advent and subsequent study of amorphous metals has caused many to believe that transformers and inductors made with amorphous metal magnetic cores have the potential to provide substantially higher efficiencies and power densities compared to conventional transformers and inductors. In particular, amorphous metals exhibit promising low-loss characteristics, leading many to believe that a magnetic core of amorphous metal would result in a transformer or inductor with increased efficiencies. However, it has proven difficult to effectively manufacture single and multi-phase amorphous metal transformer and inductor cores. In particular, amorphous metal tends to be brittle and difficult to work with and manipulate into desired shapes. Amorphous metal is manufactured in ribbon form, and the ribbon of amorphous metal is generally wound into toroidal rings of the ribbon during manufacture. Thus, the only practical shape that has been used when building transformers or inductors with amorphous metal cores is a ribbon wound oval shape. It would be advantageous to provide alternate shaped amorphous metal cores for transformers and inductors. It would be further advantageous to provide an inductor and/or transformer core assembled from amorphous metal such that the core has low loss characteristics and may be easily manufactured at a low cost.